A Pediatric Rheumatology Tissue Repository (PRTR) is a proposed resource available to investigators of the research base, as well as at the national level for multi-center studies in pediatric rheumatology. This repository provides uniform acquisition and storage of patient and control samples for research purposes. In addition, training is provided to outside centers to ensure smooth and consistent functioning in collection. The principal functions of this Core are: To collect, process and maintain biological specimens from patients with pediatric rheumatological and related musculoskeletal conditions as well as from relevant control populations for research purposes. The types of samples currently primarily include RNA, DNA, synovial fluid, synovial tissue, serum and lymphocytes; To support multi-center collection of patient and control samples nationally. The scope of specimens needed for translational research projects is extensive and can rarely be accomplished without collaborative efforts between multiple clinical investigative sites. The PRTR will assist in establishing sample collection, processing and shipping protocols and coordinate training of clinical site personnel to provide uniform sample collection. The function has been extended beyond the local research base to pediatric rheumatologists at other institutions; To allow systematic access to biological samples for investigators conducting IRB approved basic and translational studies in pediatric rheumatological disease and provide specimens to investigators in appropriate format. This will be done by tracking specimens, study information, consent information and necessary clinical classification within the Biomedical Informatics managed, web-based Biorepository (BR) and integrated Protocol Manager (PM) Software modules.